A general synthesis of the alpha-methylene lactone group found in many promising antitumor agents, from olefins is proposed. Its final and key step will be the palladium-catalyzed carbonylation of an acetylenic alcohol under extremely mild conditions. For alpha- methylene-gamma-lactones the use of diphenylethynylaluminum to transform epoxides into acetylenic alcohols is proposed. The mechanism and scope of the Pd-catalyzed carboalkoxylation will be explored. Whether the eventual location of the double bond is thermodynamically or kinetically controlled will be determined. The possible involvement of intermediate carboalkoxy palladium complexes will be checked by comparison of the results with those obtained when such species, generated stoichiometrically by known methods, are used. Deuterium labelling and kinetic studies will also be carried out. Results to be anticipated are improved efficiency and palladium use and knowledge of the synthetic uses of the reaction: possible lactone ring sizes, types of other rings to which the lactone can be fused, and stereochemistries at the ring junction. The limitations (functional group tolerance) of the reaction will also be explored. In the course of these studies partial syntheses of several natural products known to be promising cancer chemotherapeutic agents will be undertaken.